X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=block%2Fcfq-iosched.c;h=bfb396774cbb72f47f421e3d55d5bc88b07f8f4f;hb=1e3335de05da3dfbe48b8caa03db1834a2133256;hp=b6491c020f26ec53dedcbed84e20aea0a7aea299;hpb=81450b73dde07f473a4a7208b209b4c8b7251d90;p=powerpc.git

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index b6491c020f..bfb396774c 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -532,6 +532,12 @@ static void cfq_add_rq_rb(struct request *rq)
 
 	if (!cfq_cfqq_on_rr(cfqq))
 		cfq_add_cfqq_rr(cfqd, cfqq);
+
+	/*
+	 * check if this request is a better next-serve candidate
+	 */
+	cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
+	BUG_ON(!cfqq->next_rq);
 }
 
 static inline void
@@ -861,15 +867,11 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd)
 
 static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
 {
-	struct cfq_data *cfqd = q->elevator->elevator_data;
 	struct cfq_queue *cfqq = RQ_CFQQ(rq);
 
 	cfq_remove_request(rq);
 	cfqq->on_dispatch[rq_is_sync(rq)]++;
 	elv_dispatch_sort(q, rq);
-
-	rq = list_entry(q->queue_head.prev, struct request, queuelist);
-	cfqd->last_sector = rq->sector + rq->nr_sectors;
 }
 
 /*
@@ -986,9 +988,9 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	 * expire an async queue immediately if it has used up its slice. idle
 	 * queue always expire after 1 dispatch round.
 	 */
-	if ((!cfq_cfqq_sync(cfqq) &&
+	if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
 	    cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
-	    cfq_class_idle(cfqq)) {
+	    cfq_class_idle(cfqq))) {
 		cfqq->slice_end = jiffies + 1;
 		cfq_slice_expired(cfqd, 0, 0);
 	}
@@ -1051,19 +1053,21 @@ cfq_dispatch_requests(request_queue_t *q, int force)
 	while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
 		int max_dispatch;
 
-		/*
-		 * Don't repeat dispatch from the previous queue.
-		 */
-		if (prev_cfqq == cfqq)
-			break;
+		if (cfqd->busy_queues > 1) {
+			/*
+			 * Don't repeat dispatch from the previous queue.
+			 */
+			if (prev_cfqq == cfqq)
+				break;
 
-		/*
-		 * So we have dispatched before in this round, if the
-		 * next queue has idling enabled (must be sync), don't
-		 * allow it service until the previous have continued.
-		 */
-		if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
-			break;
+			/*
+			 * So we have dispatched before in this round, if the
+			 * next queue has idling enabled (must be sync), don't
+			 * allow it service until the previous have continued.
+			 */
+			if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
+				break;
+		}
 
 		cfq_clear_cfqq_must_dispatch(cfqq);
 		cfq_clear_cfqq_wait_request(cfqq);
@@ -1370,7 +1374,9 @@ retry:
 		atomic_set(&cfqq->ref, 0);
 		cfqq->cfqd = cfqd;
 
-		cfq_mark_cfqq_idle_window(cfqq);
+		if (key != CFQ_KEY_ASYNC)
+			cfq_mark_cfqq_idle_window(cfqq);
+
 		cfq_mark_cfqq_prio_changed(cfqq);
 		cfq_mark_cfqq_queue_new(cfqq);
 		cfq_init_prio_data(cfqq);
@@ -1575,6 +1581,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 		   struct request *rq)
 {
 	struct cfq_queue *cfqq = cfqd->active_queue;
+	sector_t dist;
 
 	if (cfq_class_idle(new_cfqq))
 		return 0;
@@ -1584,14 +1591,14 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 
 	if (cfq_class_idle(cfqq))
 		return 1;
-	if (!cfq_cfqq_wait_request(new_cfqq))
-		return 0;
+
 	/*
 	 * if the new request is sync, but the currently running queue is
 	 * not, let the sync request have priority.
 	 */
 	if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
 		return 1;
+
 	/*
 	 * So both queues are sync. Let the new request get disk time if
 	 * it's a metadata request and the current queue is doing regular IO.
@@ -1599,6 +1606,21 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 	if (rq_is_meta(rq) && !cfqq->meta_pending)
 		return 1;
 
+	if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
+		return 0;
+
+	/*
+	 * if this request is as-good as one we would expect from the
+	 * current cfqq, let it preempt
+	 */
+	if (rq->sector > cfqd->last_sector)
+		dist = rq->sector - cfqd->last_sector;
+	else
+		dist = cfqd->last_sector - rq->sector;
+
+	if (dist <= cfqd->active_cic->seek_mean)
+		return 1;
+
 	return 0;
 }
 
@@ -1634,12 +1656,6 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	if (rq_is_meta(rq))
 		cfqq->meta_pending++;
 
-	/*
-	 * check if this request is a better next-serve candidate)) {
-	 */
-	cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
-	BUG_ON(!cfqq->next_rq);
-
 	/*
 	 * we never wait for an async request and we don't allow preemption
 	 * of an async request. so just return early
@@ -1715,6 +1731,8 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
 	cfqq->on_dispatch[sync]--;
 	cfqq->service_last = now;
 
+	cfqd->last_sector = rq->hard_sector + rq->hard_nr_sectors;
+
 	if (!cfq_class_idle(cfqq))
 		cfqd->last_end_request = now;